1. Field
The field relates to an organic light emitting display, and more particularly to an organic light emitting display capable of displaying an image of uniform brightness and of realizing a high resolution and large area display.
2. Description of the Related Technology
An organic light emitting display displays an image using an organic light emitting diode (OLED) that generates light by re-combination of electrons and holes. The organic light emitting display has high response speed and is driven by low power consumption.
Methods of driving the organic light emitting display include a voltage driving method and a current driving method.
In the voltage driving method, a data signal voltage takes on one of a plurality gray scale voltage values and is supplied to pixels to display an image.
In some voltage driving methods, due to the characteristic variation of the driving transistors included in the pixels, the image may not be uniformly displayed.
In the current driving method, a current as a data signal is supplied to the pixels to display an image. In the current driving method, since current is used, an image can be uniformly displayed regardless of the characteristic variation of the driving transistors.
However, in some current driving methods, because a small current is used as the data signal, it is not possible to charge the desired voltage in the pixels within a short time. When the small current is used as the data signal, a large amount of time is required for charging the pixels due to load capacitance included in each of data lines. Therefore, it is difficult to apply some current driving methods to a large area display.
In addition, in some current driving methods, since a plurality of gray scales are displayed using the small current, it can be very difficult to design a data driver. Actually, since it may be very difficult to design a data driver that produces a high definition output, it may also be difficult to transmit a low gray scale data signal to the pixels. Therefore, some current driving methods may be difficult to apply to a high resolution display.